Just an update one this one, went to see the specialist yesterday (btw big shout out for the UK NHS, in the space of two weeks since I did it, I received triage, x-ray, consultation with trauma / fracture generalist, ultra-sound scan, further consultation with generalist and consultation with shoulder specialist).
The upshot is that cosmetically it won't be perfect and the bicep will bunch towards the elbow, it will still be able to operate normally without the op to reattach. The specialist said that for sports or cosmetic needs he's happy to do the op but it really isn't needed and there is discussion in the medical community as to what the long head tendon is actually for - there doesn't appear to be a direct purpose. He left the choice up to me and said he wouldn't attach the tendon to the shoulder point, he would either attach to the humorous or the pec (yes the pec!)
All in all i'll leave it for the meantime as there is no pain, he recommends mobility is kept up and 6-8 weeks rest from heavier weights but it should be ok from that point. Any future issues can be dealt with then and he left the doors open.